In the wee hours of Monday morning, six sailors will take to the Velux 5 Oceans startline in La Rochelle, France, ready to face 30,000 miles at sea alone.

Run every four years since 1982, the ultimate solo challenge is the oldest single-handed round-the-world yacht race. Its history is full of tragedy, disaster and incredible endurance.

The race involves a series of five ocean sprints within a marathon circumnavigation. In the course of the 30,000-nautical-mile race, the skippers cross five oceans solo.

This time New Zealand will feature on one of the legs, hosting the second stopover after the sailors battle the treacherous Southern Ocean in the sprint from Cape Town to Wellington.

From there they sail 4000 nautical miles to Salvador in Brazil and then on to the North Atlantic, stopping in Charleston in the United States before completing the circuit back to La Rochelle.

The race is the ultimate human endeavour. More than 500 people have been into space - fewer than 180 have sailed around the world solo.

The race is so demanding that even making the startline is a challenge.

Just six international sailors will compete in the 2010/11 edition - American Brad Van Liew, Christophe Bullens of Belgium, Canada's Derek Hatfield, Zbigniew Gutkowski of Poland and Australian Garry Golding - after two entrants failed to complete the qualification legs and meet the strict criteria to compete.

Van Liew, who is sailing in his third race, said he was disappointed for the skippers who missed out, but safety must remain paramount.

"If it was easy, everyone would do it," the veteran ocean racer said.

"I don't think anyone expected it to be this difficult to reach the starting line, and the economic times have definitely contributed to the difficulty of getting here, but here we are and there are plenty of competitive entries to make it a great race."

As well as being navigators, engineers, sailmakers and cooks, these men must also be their own doctors - and in extreme cases surgeons - trained to recognise and treat any illness they might pick up.

As part of their preparation, each of the Velux skippers underwent an intense two-day training programme from the offshore medical support doctors, where they were taught to use medical kits provided to them.

All seamen going offshore need to know what to do in case of a medical emergency, but the solo skippers face the daunting prospect of using the skills they have learned on themselves.

Part of the course involved a hands-on demonstration of learning how to suture by slicing open a pig's trotter and stitching it back together.

It may seem a little extreme, but it is necessary knowledge - the past 28 years of the solo race are littered with examples of sailors who had to deal with all manner of medical problems.

Perhaps the most extraordinary tale is from the 1998/99 race, when Russian sailor Viktor Yazikov developed an infection in his elbow after injuring it on the first ocean sprint.

Yazikov had no choice but to deal with the problem, performing open surgery on the infected wound, stopping the infection and ultimately saving his arm.

He carried on racing and even beat some of his fellow competitors into port.

Some would say it is brave, some would say it is crazy - but this is typical of the dogged determination with which these sailors will pursue their dream of racing a yacht singlehanded around the world.

30,000: the length of the Velux 5 Oceans in nautical miles, making it the longest single-handed event in the world

7,000: the amount of calories skippers will have to consume in the Southern Ocean each day

3,000: number of hours that the ocean racers will spend at sea in the solitary confinement of their yachts

250: the number packets of freeze-dried food the skippers will eat during a race

80: the speed in knots which the wind can reach in the Southern Ocean

73: the number of skippers who have finished the Velux race, only 65 per cent of starters

67: the age of Sir Robin Knox-Johnston when he completed the 2006 Velux race to become the oldest person to complete a solo round the world race

50 ft: the height waves can reach in the Southern Ocean

30: the average period of sleep, in minutes, skippers will get at any one time

7: the number of yachts sunk or shipwrecked in the race's 28-year history